perf: fastify - add ability to define response JsonSchema

[piotrfrankowski]

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Is there an existing issue that is already proposing this?

• [x] I have searched the existing issues

NestJS version

11.0.13

Is your performance suggestion related to a problem? Please describe it

Currently there is no way to define JsonSchema of the response when using fastify adapter. Fastify is using their own implementation of JSON.stringify that is more performant. However, most gains are achieved by providing the response schema that helps with serialization:

"Fastify uses fast-json-stringify to send data as JSON if an output schema is provided in the route options. Using an output schema can drastically increase throughput and help prevent accidental disclosure of sensitive information."

source

Describe the performance enhancement you are proposing and how we can try it out

I propose adding a new decorator RouteSchema that allows passing a schema object that aligns with fastify's route schema option doc

This will allow for opt-in solution that does not affect users not willing to touch the schema and is backward compatible

Benchmarks result or another proof (eg: POC)

Using this PR: https://github.com/nestjs/nest/pull/14789 Exact same endpoint with only difference being presence of schema. Return an array of object where size of array is set with limit parameter

❯ wrk -t12 -c400 -d30s http://localhost:3000/cats/no-schema\?limit\=10                    30s Py base 13:15:44
Running 30s test @ http://localhost:3000/cats/no-schema?limit=10
  12 threads and 400 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency     8.55ms   20.72ms 721.66ms   99.55%
    Req/Sec     2.69k   666.13     7.14k    63.00%
  963864 requests in 30.10s, 0.98GB read
  Socket errors: connect 157, read 197, write 0, timeout 0
Requests/sec:  32018.79
Transfer/sec:     33.31MB

❯ wrk -t12 -c400 -d30s http://localhost:3000/cats/schema\?limit\=10                       30s Py base 13:18:58
Running 30s test @ http://localhost:3000/cats/schema?limit=10
  12 threads and 400 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency     7.34ms    9.66ms 538.97ms   99.66%
    Req/Sec     2.86k   844.25    12.85k    58.12%
  1026043 requests in 30.11s, 1.04GB read
  Socket errors: connect 157, read 109, write 0, timeout 0
Requests/sec:  34082.03
Transfer/sec:     35.46MB
❯ wrk -t12 -c400 -d30s http://localhost:3000/cats/no-schema\?limit\=500                   30s Py base 13:10:28
Running 30s test @ http://localhost:3000/cats/no-schema?limit=500
  12 threads and 400 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency    91.94ms   60.54ms   1.96s    94.63%
    Req/Sec   195.42     67.25   575.00     72.17%
  70111 requests in 30.08s, 3.04GB read
  Socket errors: connect 157, read 549, write 1, timeout 143
Requests/sec:   2330.69
Transfer/sec:    103.50MB

❯ wrk -t12 -c400 -d30s http://localhost:3000/cats/schema\?limit\=500                      30s Py base 13:13:42
Running 30s test @ http://localhost:3000/cats/schema?limit=500
  12 threads and 400 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency    77.15ms   60.45ms   1.98s    98.06%
    Req/Sec   242.30     76.96   545.00     66.23%
  86986 requests in 30.10s, 3.77GB read
  Socket errors: connect 157, read 518, write 3, timeout 131
Requests/sec:   2889.95
Transfer/sec:    128.34MB

❯ wrk -t12 -c400 -d30s http://localhost:3000/cats/no-schema\?limit\=1000                  30s Py base 13:14:23
Running 30s test @ http://localhost:3000/cats/no-schema?limit=1000
  12 threads and 400 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   146.84ms   68.28ms   1.95s    86.23%
    Req/Sec   102.87     36.01   313.00     70.78%
  36958 requests in 30.09s, 3.20GB read
  Socket errors: connect 157, read 517, write 3, timeout 169
Requests/sec:   1228.06
Transfer/sec:    108.96MB

❯ wrk -t12 -c400 -d30s http://localhost:3000/cats/schema\?limit\=1000                     30s Py base 13:15:08
Running 30s test @ http://localhost:3000/cats/schema?limit=1000
  12 threads and 400 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   131.42ms   64.31ms   1.97s    88.08%
    Req/Sec   124.78     52.96   310.00     63.03%
  43661 requests in 30.10s, 3.78GB read
  Socket errors: connect 157, read 431, write 0, timeout 162
Requests/sec:   1450.58
Transfer/sec:    128.70MB

@ MacBook Pro M1 Max

[micalevisk]

can you show an example on how the usage of this feature would look like?

[piotrfrankowski]

@micalevisk Sure, I can create an example repo later, but here's a quick showcase of what I did for the POC:

import { Body, Controller, Get, Param, Post, Query } from '@nestjs/common';
import { RouteSchema } from '@nestjs/platform-fastify';
import S from 'fluent-json-schema'
import { CatsService } from './cats.service';

const catSchema = S.object()
  .prop('id', S.number())
  .prop('name', S.string())
  .prop('age', S.number())
  .prop('breed', S.string())
  .prop('createdAt', S.string())

const schema = S.object()
  .prop('data', S.array().items(catSchema))
  .valueOf()

@Controller('cats')
export class CatsController {
  constructor(private readonly catsService: CatsService) {}

  @Get('/schema')
  @RouteSchema({
    response: {
      200: schema,
    },
  })
  async findAll(@Query('limit') limit: string): Promise<Cat[]> {
    return this.catsService.findAll(limit ? +limit : 10);
  }

  @Get('/no-schema')
  async findAllNoSchema(@Query('limit') limit: string): Promise<Cat[]> {
    return this.catsService.findAll(limit ? +limit : 10);
  }

[piotrfrankowski]

I've rebased the PR

[Forceres]

Any updates?

[piotrfrankowski]

@micalevisk @kamilmysliwiec Anything else needed that I should add to get that in? :)

[Forceres]

Looks like fastify is not in priority.

[micalevisk]

to be honest, I'm not a fan of introducing new platform-specific decorators. But I can't see a better and idiomatic way to support that feature

[kamilmysliwiec]

Lets track this here https://github.com/nestjs/nest/pull/14789